Automated floor wrenches for drilling rigs are known. These existing devices do have, however, deficiencies and shortcomings. Some devices are known to have two rams opposed to each other, each ram having a pair of tong dies to contact and grip drilling pipe. Other devices are known to have three rams spaced 120 degrees apart around the drill pipe, each ram having a tong die to contact and grip the pipe.
The problem with these devices is that the force required for the dies to contact and grip the pipe can score or damage the pipe surface, thus resulting in premature pipe wear. In addition, the use of only two or three rams requires significant force placed on two, three or even four points on the circumference of the pipe by the tong dies, which can cause the pipe to be squashed or deformed at those points, again resulting in premature wear and service life for the pipe.
When automated floor wrenches are used on drilling rigs, it is known to use top drives for rotating the drill string and drilling operators have been known to use the top drive to make joints between sections of drill pipe instead of using the automated floor wrench. Top drives can produce large amounts of torque, far more than what is necessary to properly torque sections of drill pipe together. Using the top drive to make the joints can apply excessive rotational force to the automated floor wrench, which is still being used to grip to lower section of drill pipe, and can cause damage to the floor wrench.
It is, therefore, desirable to provide an automated floor wrench for a drilling rig that overcomes the shortcomings of prior art devices.